Which SQL statement correctly creates a B-tree index on the column last_name of the table employees?

easy📝 Syntax Q12 of 15

SQL - Indexes and Query Performance

Which SQL statement correctly creates a B-tree index on the column last_name of the table employees?

ACREATE INDEX idx_last_name ON employees USING HASH (last_name);

BCREATE INDEX idx_last_name ON employees (last_name) USING BITMAP;

CCREATE INDEX idx_last_name ON employees (last_name);

DCREATE INDEX idx_last_name ON employees USING FULLTEXT (last_name);

Step-by-Step Solution

Solution:

Step 1: Identify default index type in SQL
By default, CREATE INDEX creates a B-tree index unless specified otherwise.
Step 2: Check syntax correctness
CREATE INDEX idx_last_name ON employees (last_name); uses correct syntax without specifying a different index type, so it creates a B-tree index on last_name.
Final Answer:
CREATE INDEX idx_last_name ON employees (last_name); -> Option C
Quick Check:
Default index type = B-tree [OK]

Quick Trick: Default index type is B-tree unless stated otherwise [OK]

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